Special Senses Chapter 16 Flashcards
Where are:
-More than half of the sensory receptors in the human body located
Eyes
A large part of the cerebral cortex is devoted to processing _______ information.
Visual
(Accessory structures of the eye)
What is the:
-Eyelid
Palpebrae
(Accessory structures of the eye)
What is the:
-Layer of connective tissue which gives eyelid form and support
Tarsal plate
(Accessory structures of the eye)
What is:
-Located inside of the tarsal plates -secrete oils which keep eyelids from adhering to each other.
Tarsal glands (Meibomian glands)
What is:
-An infection of the tarsal gland producing a cyst on the eyelid
Chalazion
(Accessory structures of the eye)
What is:
-The thin protective membrane composed mainly of stratified columnar epithelium
Conjunctiva
(Accessory structures of the eye)
What:
-Lines inner eyelids
Palpebral conjunctiva
(Accessory structures of the eye)
What:
-Passes from the eyelids onto the anterior surface of the eye
(Does not cover the cornea)
Bulbar (Ocular) conjunctiva
What is:
-Inflammation caused by bacteria
-Other forms caused by irritants such as dust and smoke
Conjunctivitis (pink eye)
(Accessory structures of the eye)
What:
-Help protect from foreign objects, perspiration and sunlight
Eyelashes and Eyebrows
(Accessory structures of the eye)
What:
-Are found at base of eyelashes
Sebaceous glands
What:
-Is an and infection of sebaceous glands
Sty
(Accessory structures of the eye)
What is:
-The gap between the eyelids
Palpebral fissure
(Accessory structures of the eye)
What:
-Contains sebaceous and sudoriferous glands
Lacrimal caruncle
What:
-Manufactures and drains tears
Lacrimal Apparatus
(Lacrimal Apparatus)
Lacrimal gland drained by 6-12 ________ _______ ducts > Lacrimal puncta > superior and inferior ________ __________ > lacrimal sac > ____________ duct > inferior meatus (nasal cavity)
-Excretory lacrimal ducts
-Lacrimal canaliculi
-Nasolacrimal duct
What:
-Cleans, lubricates and moistens the eyeball
Lacrimal Secretion
What 4 things does the Lacrimal secrete?
How many ml/day is normal?
-Water
-Salt
-Mucus
-Lysozyme
-1ml/day
Describe the eye structure
-Hollow
-Spherical
-Approximately 1 inch in diameter
(Eye structure)
What contains:
-Sclera and cornea
Outer fibrous tunic
Which part of the eye:
-Focuses light onto retina
-Covers the iris
-Avascular
Cornea
(Eye structure)
What has these 3 layers:
-Nonkeratinized stratified squamous(outer)
-Collagen and fibroblasts (middle)
-Simple squamous (inner)
Outer fibrous tunic
Which part of the eye is:
-“white” of the eye
-Dense connective tissue
-Gives shape to the eye and makes it more rigid
Sclera
(Eye structure)
What contains:
-Choroid
-Ciliary body
-Iris
Vascular Tunic (Uvea)
(Eye structure)
What part of the eye:
-Highly vascular
-Provides nutrients to the posterior part of the retina
-Contains melanocytes to absorb light and prevent glare
Choroid
(Eye structure)
What contains:
-Ciliary processes
-Ciliary Muscle
Ciliary Body
(Ciliary Body)
What is:
-The extension of the ciliary process which hold the lens
Zonular fibers of lens
(Eye structure)
What is:
-The circular band of smooth muscle which alters the shape of the lens for far and near vision
Ciliary Muscle
What is the:
-A thin muscular diaphragm that regulates the amount of light entering eye
Iris
Which cells:
-Contain melanin
(amount of melanin determines eye color)
Chromatophores
The muscles:
Circular - Parasympathetic:
Does what to the pupil
Constricts pupil
The muscles:
Radial-Sympathetic:
Does what to the pupil
Dilate pupil
Which part of the eye:
-Contains a pigmented layer and neural layer
-Has 3 layers of _______ neurons
The Retina
Order of nerve conduction of the Retina:
Photoreceptor layer > Outer _________ layer > _________ neurons > Inner Synaptic layer > ___________ cells
-Synaptic layer
-Bipolar neurons
-Ganglion cells
What is the:
-Jagged anterior edge of retina
Ora serrata
What are the 2 types of photoreceptors called?
Rods and Cones
What is:
-Most important for black and white vision in dim light
-Allow us to see shapes and movement
Rods
In dim light such as moonlight, only ____ functions
Rods
What:
-Allows for color vison and sharpness of vison in bright light (visual acuity)
Cones
What are the 3 types of cones:
-Blue cones (S cones)
-Green cones (M cones)
-Red cones (L cones)
What is:
-The absence or deficiency of one of the 3 cones resulting in the inability to distinguish between certain colors
Color blindness
(Retina)
What is:
-A patch of cells in the exact center of posterior retina
-Contains a tiny pit called the fovea centralis
Macula lutea
(Retina)
What is:
-A dense concentration of cones in the macula (rods are absent)
-Area of our sharpest vision
Fovea centralis
What disorder is:
-Degeneration of the area of the macula lutea
-Usually 50 or over
-Loss of straight-ahead vision
-Retains peripheral vision
Age-related macular degeneration (AMD)
What disorder is:
-Distorted or lost vision in corresponding visual field
-Reattached by laser surgery or cryosurgery
Causes:
-Trauma, age-related degen. or various eye disorders
Detached retina
(Retina)
What is:
-Medial to the macula lutea
-______ ____is the opening through which axons of ganglion neurons exit as the optic nerve
Optic disc (blind spot)
(Retina)
What:
-Contains no rods or cones, so vision is absent here
Optic disc (blind spot)
What is:
-Behind the pupil and iris
-Made up of proteins called crystallins
-Is avascular and transparent
-Functions to focus images on the retina
Lens
What occurs when:
-Lens becomes cloudy due to changes in the lens proteins
-Most commonly occurs with aging
-Lens is replaced with an artificial one
Cataracts
What 2 cavities is the interior of the eyeball divided into
-Anterior cavity
-Vitreous chamber
The 2 chambers in the Interior of the eyeball is divided by what?
The lens
(Anterior cavity has 2 chambers)
Which chamber is:
-Between the cornea and iris
Anterior chamber
(Anterior cavity has 2 chambers)
Which chamber is:
-Behind the iris and in front of the lens
Posterior chamber
The anterior cavity is filled with a watery substance called the _________ _______.
-Aqueous humor
Aqueous humor is filtered from blood capillaries in the _______ _________.
It is drained by the _______ ______ ______ and then into blood.
-Ciliary process
-Scleral venous sinus
What nourishes the lens and cornea?
Aqueous humor
What disorder is:
-Abnormally high intraocular pressure due to build up of aqueous humor in the anterior cavity
-Persistent pressure leads to vision loss and blindness
Glaucoma
What disorder:
-The fluid can then put pressure on the lens and consequently the vitreous body and neurons of the retina
-Treated with eye drops to reduce production of aqueous humor and increase drainage
Glaucoma
What part of the eye:
-Lies between the lens and retina
The vitreous chamber
The jelly-like substance is called the…?
Vitreous body
The vitreous body is not replaced, but formed during __________ ______.
Embryonic life
Which part of the eye:
-Contains phagocytic cells which remove debris
The vitreous body
Which part of the interior eye:
-Narrow channel that runs through vitreous body
-In fetus, was occupied by the hyaloid artery
Hyaloid canal
(Image Formation)
Images are formed on the _______ of the eye.
Retina
(Image Formation)
-In order for an image to be formed, what 3 processes must be understood?
-Refraction
-Accommodation
-Constriction of the pupil
What occurs when:
-Bending of light rays as they travel from air into a different media
Refraction